This invention relates to techniques for applying security coatings to microelectronic circuits.
Coatings are applied to microelectronic circuits to restrict reverse engineering of the circuit layout and deny access to embedded codes. Coatings can provide a physical barrier that destroys the underlying components when the coating is manipulated in some fashion, e.g. cut or tampered with. Current techniques, in general, involve applying one or more single-layer or single-component coatings, e.g. as depicted in FIG. 1, where a primer 10 and a protective coating 12 cover a circuit set or die 14. Coatings may also provide a protective barrier to certain forms of electromagnetic inspection.
Despite significant strides in this area, among them the use of thermal spray to apply coatings described in U.S. Pat. Nos. 6,319740, 6,287,985, 6,110,537, 5,877,093 and 5,762,711, industry desires higher security as more valuable information is stored in electronic circuits that are increasingly used to support the economic and sustaining infrastructures of the world. The higher value information resident in electronic circuits and their designs raises the risk of unauthorized reverse engineering of the protected system and a resultant loss of valuable information through unauthorized duplication, spoofing and use of such “target devices”, any electronic system that contains components that require protection from physical, chemical, electrical, acoustic or spectral methods of inspection.